Soil biodiversity is critical to ecosystem functioning, but our understanding of the richness and distribution of soil organisms lags far behind that of biodiversity above ground. The difficulties of detecting organisms that spend all or most of their time living below ground and a shortage of skilled scientists able to identify them have contributed to our general lack of knowledge. This is particularly true in alpine zones which support some of our most natural habitats and provide important ecosystem services, including supporting unique biodiversity, carbon storage and water supply. The difficulty of accessing remote locations such as the alpine zone compounds the challenges of difficult to detect organisms.
For these reasons, new approaches are needed if we are to fully understand the distribution of soil biodiversity and its implications for the functioning of alpine ecosystems. Use of DNA to detect the presence of organisms from environmental samples has high potential in this regard and in this project, we explored how this could be combined with citizen science to extend the reach of biodiversity surveys.
Stage
Work in ProgressDirectory of Expertise
Purpose
Soil biodiversity is vital to maintaining ecosystem functions including carbon and nutrient cycling and for the support of plant and animal diversity aboveground. Scotland’s alpine zone contains some of our most natural habitats, supplies us with clean drinking water, supports important carbon stocks and is home to charismatic plants, birds and mammals. However, our knowledge of alpine soil biodiversity has been limited by difficulties in detecting belowground organisms, a shortage of skilled taxonomists, and the challenges of accessing remote areas.
Recent advances in DNA sequencing technology and reductions in costs have made analysis of DNA in soil or water an increasingly attractive option for assessment and monitoring of biodiversity. Additionally, and particularly since the start of the Covid-19 pandemic, there has been a rising trend in recreational access to mountain areas, as people seek the benefits of time in nature. These trends provide an opportunity, both to advance our scientific knowledge of mountain soil biodiversity, and to engage and educate the public about its importance.
Citizen science provides opportunities for the public to become involved with scientific research and enables knowledge exchange and insight into scientific methods. We collaborated with the charity Plantlife Scotland, as part of their Cairngorms Rare Plants and Wild Connections project, to trial a citizen science DNA approach to exploring soil fungal diversity in the alpine zone of the Cairngorms National Park.
Fungi are an essential component of all ecosystems, with important roles in decomposition and nutrient cycling but we have limited knowledge of their distribution and diversity. They can however be readily detected by extracting their DNA from soil. The Cairngorms National Park contains one third of the UK’s alpine zone (land above 600 metres) and 58 mountains with an elevation greater than 3000 feet (914 m) known as Munros which are a popular target for hillwalkers and these 58 mountains were chosen as the focus of our study.
Figure: Fungi are essential components of soil biodiversity and have important roles in nutrient cycling. Since they can only be detected above ground when they produce fruiting bodies (which may occur only rarely) sampling them directly by extracting DNA from soil provides a much more complete picture of their diversity and distribution.
(All photographs by Andrea Britton)
Results
Our project was promoted both to hill walking groups in and around the Cairngorms National Park area and more widely on social media. Volunteers could ‘adopt’ one or more of the 58 Munros in the Cairngorms National Park and were sent a surveyor’s pack containing all the required sampling equipment, full instructions, a reply-paid envelope for returning samples and some information about the plants they might encounter in the alpine zone.
We asked volunteers to photograph the vegetation and collect a small soil sample at each of three pre-defined points in a grassland, dwarf-shrub heath and moss heath area, plus a ‘lucky dip’ sample at a location of their choosing. During the summer of 2021, volunteers visited 55 of the 58 Munros in the National Park and collected a total of 219 soil samples for DNA analysis of fungal communities.
Figure: Summary of volunteer effort during field sampling in summer 2021.
Analysis of the DNA extracted from the 219 soil samples detected 2748 fungal taxa (species or broader groups), including several species new to the UK. We found that:
- soil under each vegetation type (e.g., grassland or moss heath) supported a different community of fungi,
- communities under the same vegetation type were similar across all the mountains sampled,
- and fungal communities under grassland contained more species per sample than dwarf-shrub and moss heaths.
Figure: The number of fungal species detected in each sample of grassland, dwarf-shrub and moss heath.
The National Biodiversity Atlas of Scotland contains 123,600 records of 3781 species of fungi in the Cairngorms National Park collected between 1850 and the present day. However, in just three months our survey has collected 17462 records comprising 2748 species.
The data from our survey adds significantly to our knowledge of the distribution and diversity of fungi in alpine soils and can be used to start identifying which habitats and locations are particularly important for conservation of fungal diversity.
Benefits
The success of this survey and the scale of the data produced demonstrate the potential for citizen science and DNA approaches to enable large-scale biodiversity assessment in mountain soils. As a result of this work, a research paper and outreach materials (in collaboration with Plantlife) are now in preparation.
Since the DNA approach is not reliant on finding fungal fruit bodies it provides a much more comprehensive picture of fungal diversity in soil than was previously possible. This type of data could provide a much more secure basis for conservation decisions than ad hoc records of fruit bodies.
Feedback about the project from the citizen scientists was very positive, many people commented that they had appreciated the chance to make a positive contribution to science and conservation while doing something they enjoyed (hillwalking). The project also contributed to raising awareness of soil biodiversity and its importance, not only among the citizen scientists but also with people they met out on the hills who were curious about what they were doing.
In addition, the data collected by the project provides a baseline assessment of alpine fungal communities in the Cairngorms, against which the effects of future climate and environmental change could be assessed. As the climate changes, distributions of alpine species are also likely to change, and understanding which species are moving and how fast will be vital to predict how ecosystem function might change in future.